hey everyone wondered if anyone could help, 3 days ago I purchased a mondeo mk3 tdci privately, and for the past day or so iv been having problems starting it, I turn the key in the ignition and the immobiliser, flashes away at me, at first it took a few attempts at turning the key to get it to go through and start the engine, I took it down to a local garage and he said what it seems to him is that one key with the 3 buttons opens and locks but the other just turns the ignition barrel so advised me to hold the 3button key close to the barrel, this I thought worked unil today, today I don't think its took less that 15mintes at a time to get it to start, luckily I have a friend who works at ford so iv took it along to him after explaining my problems over the phone and said the key at turns the ignition just wants coding, so after him telling me the price I took it down and he had a go at recoding it, NO LUCK!, the computer he was using to recode was saying there was a fault and it was possibly the PATS module, but told me to eliminate the ring around the ignition first and purchase one of those, after finding out that the £150 inc VAT a ford I went to a local dismantlers that he said was good and got one, come home changed it over still no luck, so the next thing is the PATS module, what Im guessing I need to know now is where is it? can it be fixed? is it simple and is it expensive? as its my work car so need it fixing to earn my bread and butter,

hanks for taking the time to read this, and thanks for the replies if any in advance

this might be wrong but i just read on another forum that some mk3's had external PATS module beside handbrake & some mk3's have it incorporated into the ECU in tandem with the transceiver around ignition barrel. someone here should know though. I had a similar problem on another car & it drove me crazy!

yes its driving me !Removed! nuts and after having a new key cut at Ford and them programming both keys, on top of purchasing another receiver that goes around the barrel, im trying to eliminate starting from the cheapest and working my way upwards but the only thing I see now it it being what my friend at ford said and that's the Pats module its self, but I haven't a clue when it comes to diagnostics and electrics, so wouldn't even know who to take it to? could it be replaced with another or will it need a whole new ecu?

The passive anti-theft system (PATS) uses radio frequency identification technology and a unique encryption code to deter a drive away theft. Passive means that it does not require any activity from the user.

Encoded Ignition Key

The PATS uses a specially encoded ignition key. Each encoded ignition key contains a permanently installed electronic device called a transponder. Each transponder contains a unique electronic identification code which may be any one of millions of combinations. Each encoded ignition key must be programmed to the vehicle's PATS control function within the powertrain control module (PCM) before it can be used to start the engine. There are special diagnostic repair procedures outlined in this manual that must be carried out if an encoded ignition key needs to be changed.

The PATS transponder key is identified by a blue insert. Previous PATS transponder keys that have a red insert are not compatible with this vehicle and must not be used.

Only Ford approved ignition keys should be used as some aftermarket encoded ignition keys not purchased from a Ford approved source may fail to operate especially at extreme temperatures.

NOTE: If a non programmed key has been used, further key reading is inhibited for 20 seconds. During this 20 seconds, no ignition key will start the engine.

A minimum of 2 encoded ignition keys must be programmed to a vehicle in order for the engine to start. A maximum of 8 ignition keys may be programmed to a vehicle. The PATS control function within the PCM will enter Anti-Scan Mode if an attempt to start the vehicle with a non programmed ignition key (with the correct mechanical cut) is made.

PATS Control Function

The control functions are contained in the PCM. This module carries out all of the PATS functions, such as receiving the identification code from the encoded key and controlling engine enable. The PCM initiates the encoded key interrogation sequence when the vehicle ignition switch is turned to II or III. When the key is turned to the 0 position, the PCM will remain powered up for approximately five seconds. This is the maximum time allowed for the insertion of a second key to initiate the customer key programming sequence.

Transceiver Module

The transceiver module communicates with the PATS encoded ignition key. This module is located behind the steering column lower shroud and contains an antenna connected to a small electronic module. During each vehicle start sequence the transceiver module reads the encoded ignition key identification code and sends data to the PATS control function within the PCM. No re-initialization needs to occur with the removal or installation of a new PATS transceiver.

hope that makes it a bit clearer. looks like the PATS IS incorporated into the ECU/PCM

mate I'd take it to either a good auto-sparky,or to another Ford dealer. When you told me your mate said to look for the module etc,I thought if you went to Ford as a customer,they wouldnt say that. Their IDS/VMM should be able to pinpoint exactly whats up. Hell I know guys on another forum with IDS that'd definitely crack it,but theyre in another country.

ps:Ive PM'd you the self-test guide & wiring diagrams for the PCM/Transceiver. As I said if you're no good with a multimeter,an auto-sparky would suss it out

hi yes he works at the Ford dealership in chapletown, and told me that it seems to be the Pats and his boss even had a play and that's what he said too, and that if it was he would expect it to be an expensive job to fix and maybe more than what the cars worth

Thanks for the feedback it really is appreciated, iv been and purchased the ecu/pcm and all the barrels, only 1 key though so hoping he will programme my other one, going to have a go at changing them all over in the morning then call out the local auto electrician, i just hope its not a brake in the wiring

ok.was it giving you any codes? Is it communicating with ecu & immobiliser? guy on other forum is asking.he thinks you're doing the wrong thing by installing the other ecu etc right away,in case its something else(thats correctable)

Hi i believe it is communicating as and when it wants to, like i said its been taking about 100 turns of the key and thats not 1 less, it really has become a nightmare and its just a case of pot luck if it starts or not, when my friend had it hooked up to his computer it was coming back as a pats module fault, so i bought a ecu&pcm and all the door locks and matching keys yesterday from a local garage that just deals with ford and he said that he would be amazed if what im doing didnt fix it

do you know what ecu you need now then? just outta curiosity did it show any codes when it wouldnt start(when the guy at ford hooked it up to IDS?). guy on another forum is asking.

was it communicating with immobiliser system? he seems to think it should have a specific code if its not communicating with PATS. when i told him that its only 1 in 100 turns he maintains its probably not the ECU